Field of the Invention
The present invention relates, in general, to improved systems, methods, and devices for monitoring the oral motor kinetics of an infant during nutritive sucking (NS) and non-nutritive sucking (NNS).
Introduction
As the ability of an infant/newborn to feed by mouth safely and efficiently is dependent on the proper development of his/her oral feeding skills, researchers have developed a number of systems for monitoring infant sucking. Sucking is the mechanism used by an infant to feed in order to obtain milk/nutrition. Sucking comprises two components, Suction and Expression. Suction corresponds to the generation of a negative pressure in the oral cavity (intraoral) which draws the liquid into the mouth. Expression corresponds to the generation of a positive pressure when the tongue squeezes the nipple against the hard palate which ejects the liquid into the mouth. The systems for monitoring infant sucking fall into three categories. The first category measures the number of sucks by the number of pressure changes inside the nipple/bottle (1-3). The second monitors only the Suction component of sucking (4, 5). The third system monitors both components of sucking, Suction and Expression (6-9). Suction is defined as the negative intra-oral pressure exerted to draw milk from a bottle or breast into the mouth. Expression, is defined as the compression and/or lengthwise stripping of the nipple (bottle or breast) by the tongue, pushing up against the infant's hard palate to eject milk into the mouth (10, 11).
As the infant's oral motor skills develop, it has been shown that the Expression component appears first, followed by the Suction component (9). Infants using the Expression component alone can feed by mouth safely and successfully, albeit not as efficiently as when using a rhythmic alternation of Suction and Expression (8, 9); the latter being recognized as the full-term sucking pattern (6, 7, 9). These studies demonstrate the physiologic and functional importance of the Expression component of sucking. It has been speculated that compression primarily occurs with immature Expression, while stripping which also includes compression occurs with mature Expression. In brief, studies using monitoring systems that do not include both components of sucking, and in artificial settings, lead to an incomplete understanding of oral motor kinetics and feeding skills. This not only threatens the infants' safety and competence when feeding by mouth, but it also provides an inaccurate knowledge base for the development of oral feeding interventions.
Background of the Present Invention
An embodiment of the present invention measures oral motor kinetics of an infant. Both the Suction and Expression components of sucking were measured using a miniature pressure transducer for each component (total of 2 transducers), during normal oral feeding sessions (FIG. 1). The first system allowed monitoring with a standard bottle as used in nurseries, and in which infants obtained milk regardless of the sucking pattern they used, Expression alone or alternation of Suction/Expression. The individual Suction and Expression pressure traces were recorded simultaneously; and the overall oral feeding performance was characterized by evaluating two parameters, the percent of overall milk transfer [(volume taken/volume to be taken)×100] and the rate of milk transfer over the entire feeding period (ml/min) (8). Referring now to FIG. 1, pressure transducer plates 103 are associated with the nipple of instrumented bottle 101. A soft Silastic tubing 105 provides covering for the transducer 103 when transducer 103 is partly located outside of the nipple of bottle 104. This prevents the transducer 103 from being in direct contact with infant's oral cavity. Gray shading 102 indicates fluid for delivery through the nipple. Transducer 103 may measure negative pressure (Suction) or positive pressure (compression) or both. Suction pressure signal 109 and Expression pressure signal 111 are transmitted via wires in communication with signal processor 113. The wires are located within tubing 107. The tubing may be for example PE. In one embodiment the tube 105 is connected to tube 107. However, the signal may be transmitted wirelessly also. The processed signal [−] or [+] is displayed on monitor 115. The negative pressure is detected at transducer 103 (illustrated as a dot connected to wire 112 in the lower portion of the tip of the nipple).
The stages of infant feeding were recorded. A 5-point scale (1A; 1B; 2A; 2B; 3A; 3B; 4; 5) characterizing five developmental stages of nutritive sucking during bottle feeding, beginning with the appearance of only the Expression component, followed later by that of the Suction component (FIG. 2), was validated. Immature sucking is characterized primarily by the use of Expression-alone (Stage 1, which is less efficient); while mature sucking, as seen in infants born at term gestation, is characterized by the rhythmic alternation of Suction/Expression (Stage 5, which is more efficient). A direct relationship was demonstrated to exist between these developmental stages and the oral feeding performance parameters, as defined above (9).
The understanding of the maturation process in infant sucking skills, gained with measurements from the first OMK system, has allowed the development of preventive and therapeutic interventions to assist infants with oral feeding difficulties (12-16).